This invention relates in general to infrared radiation and, more particularly, to an infrared emitter panel and method of producing same.
The utilization of infrared emitters of the flat panel type has gained wide acceptance in the industrial field as within equipment for baking, curing, plasticizing, shrink wrapping, and the like. Fundamentally, such panels embody a heating element consisting of an electrical resistor of non-helical form; being customarily of the hair pin or serpentine configuration; and with such element being embedded within refractory material. In view of the non-helical character of such elements, there has been the problem of providing for the expected linear expansion of such elements during heating, and with complementary volume for assuring contraction. If such provision were not made, severe distortion and failure of the element would quickly occur with full impairment of the panel.
Heretofore one expedient for providing requisite volume and expansion and contraction of such elements is set forth and described in U.S. Pat. No. 3,809,859 granted May 7, 1974 wherein the element is maintained in sandwich form between a pair of confronting sheets of refractory material by means of a strip forming anchor extending across the central portion of the heating element to thereby allow the end portions to remain free for suitable linear movement under heating or cooling as the case may be.
Therefore, it is an object of the present invention to provide an infrared emitter panel wherein the non-helical heating element is fully encased within a body of refractory material wherein there are provided expansion chambers for allowing uninhibited linear movement of the various segments of the heating element.
It is another object of the present invention to provide an infrared emitter panel having a non-helical heating element encased within a unitary body of refractory material thereby avoiding the incorporation of cooperating discrete refractory sheets as has been customary, and with such unitary body having enclosed chambers for accommodating the linear expansion and contraction of the heating element.
It is a further object of the present invention to provide a unique method for producing an infrared emitter panel which obviates the necessity of assembling a multiplicity of discretely and independently formed components, such as refractory panels, heating elements, and anchoring devices for the heating element.
It is a further object of the present invention to provide a method of the character stated which may be easily and economically performed; wherein contraction and expansion chambers are provided for the heating elements without preforming through the utilization of extrinsic tools or devices.
It is a still further object of the present invention to provide an infrared emitter panel of the character states which is most reliable in usage; having marked longevity for operational purposes; and which permits of utilization of resistors having substantially greater coefficient of contraction and expansion than heretofore considered feasible in such emitters; and which have marked emissivity factors.